just speaking to the boston law enforcement source, a federal source earlier today, and a sense of is it domestic? is it international, the answer i got from both is we don't know. to drew's point, that type of a device, al qaeda has used, taliban has used. you see them in pakistan. however, they have nothing to trace to any international group or individual and they shrug and say sadly in today's age, it's very rare, but if you want to learn how to do this, unfortunately, you can on the internet. >> we'll have more on the investigation throughout this hour. i want to go next to gary tuchman at a vigil wrapping up in the dorchester neighborhood. gary, tell us about what you've seen. >> the candle light vigil has come to an end, but people don't want to leave just yet. a sense of community and togetherness that's taken place here. and this was an amazing gathering because there were probably about 1,100 or 1,200 people here, this was all word of mouth. people came with their candles and honored the three people who have died so far in this catastrophe. and also, pledged togetherness to